It is difficult for a person in the water to climb into a boat by getting over the edge of the latter: because there is no bearing surface for the feet, the person is in practice obliged to grasp the edge of the boat with two hands and to haul himself over the edge with the strength of the arms alone. This difficulty may occur irrespective of the type of boat, for example for a person who has fallen overboard. It is also the case with life rafts, with the particular difficulty that the person in the water may be in a state of panic and/or exhausted, or even injured, which makes it all the more problematical for him to get on board without outside assistance.
Certainly, various items of accessory equipment are known that are designed to be mounted on a boat, notably an inflatable life raft, in order to help a person in the water climb into the boat. These may notably be side halyards or various protrusions on the side of the boat designed to be grasped by the person in the water, flexible ladders (rope ladders or strap ladders) fixed to one edge and floating in the water, bars for example made of wood coupled by flexible ties to one side of the boat, etc. However, because of the very fact that they lack rigidity, these items of equipment are not easy to use, particularly for people who are not experienced in their use. In addition, it is also necessary for the person in the water to make a physical effort to haul himself up onto these items of equipment, which is difficult when this person is exhausted and/or injured.
Furthermore, it is necessary to ensure that the conformation of the boat is such that, when it is fitted with a tent fabric (or canopy) which covers it for the protection of the people on board, the aeration of the internal volume is appropriately provided, and this is done while as much as possible preventing the entry of water, including on a rough sea.